Water hardness in Houston
6.4 gpg moderately hard
Tap water in Houston is moderately hard: 6.4 gpg (110 mg/L · 6.2 °dH · 11 °fH).
Source: City of Houston 2024 Water Quality Report (2024) · data checked 2026-10-19
Range across supply zones: 43–137 mg/L.
The figure is for the City of Houston main water system: an average of 110 mg/L (6.4 gpg) in the 2024 report, with samples between 43.4 and 137 mg/L. Kingwood, Willow Chase and several municipal utility districts are separate public water systems with their own tables and are not included. If you live in one of those areas, use that system's report.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6.4 gpg |
|---|---|
| Utility | City of Houston Public Works (Houston Water) |
How Houston compares
- Tap water in Houston is 29 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 954 of 1372 in the United States (1 = hardest); 29 % of these cities have softer water.
- In Texas it is number 48 of 60 cities; the regional median is 8.6 gpg.
- Nearest city with clearly softer water: College Station, 134 km away (0.4 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Houston
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Houston water hard or soft?
It is moderately hard: 110 mg/L as CaCO₃ (6.4 gpg, 6.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Houston safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Houston water?
6.4 gpg, equal to 6.2 °dH, 11 °fH or 110 mg/L calcium carbonate.
What dishwasher salt setting should I use in Houston?
For 110 mg/L (6.2 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Houston?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Houston 2024 Water Quality Report (2024). Method: figure published by the water supplier. City of Houston 2024 Water Quality Report · Outdated figure? Tell us